The purpose of this project is to design and build an impact noise generator whose peak level, rise time, and decay can be experimentally manipulated so that the effects of these parameters on hearing loss can be studied in laboratory animals. Lack of such a generator has greatly contributed to the paucity of controlled laboratory studies of impact noise effects on hearing. Because of the high instantaneous peaks and rise times of impact noise, it cannot be recorded and reproduced in the conventional manner with audio equipment.